Tropical Marine Algae. IX. A New Sesquiterpenoid Metabolite From the Red Alga Laurencia marianensis

An investigation of the natural products chemistry of the red alga Laurencia marianensis Yamada, a species whose chemistry has not previously been described in the literature, yielded the new metabolite 1-[(3'S*,3a'lR*,4'R*,7'S*,7a'S*)-7'-bromo-7a'-methyl-3'-(1'-methylethyl)octahydro-1'H-inden-4'-yl] ethanone (1) and the known metabolites deoxyprepacifenol (2) and pacifenol (3). The full n.m.r. characterization of (2) and (3) is reported for the first time.